The efficiency of a steam turbine engine is 35%. If the energy output is 750kJ, the total mechanical energy energy input is
Since the efficiency of the steam turbine engine is 35%, this means that 35% of the energy input is converted into useful work. Therefore, the energy input can be calculated by dividing the energy output by the efficiency:
Energy input = Energy output / Efficiency
Energy input = 750 kJ / 0.35
Calculating this, the total mechanical energy input is approximately 2142.86 kJ.